Truffle Genus: Tuber

Tuber canaliculatum ascospore scale = 10 µm Tuber melanosporum ascospore scale = 10 µm

Kingdom: Fungi Phylum: Ascomycota Order: Pezizales Family: Tuberaceae   Tuber maculatum ascospore scale = 10 µm

Spore Characters

Surface: Ornamented with spines or a honeycomb-like reticulum 2-5 (-8) µm tall.
Shape and Size: Globose to ellipsoid, 32-88 x 21-54 µm (excluding ornamentation).
Wall: Single, 2-5 µm thick.
Color in Water: Pale brown to dark brown.
Melzer's Reaction: Not distinctive.
Comments: Spores of Tuber species vary greatly in size, even within a single sporocarp. This relates to number of spores borne within eacg ascus, which may range from one to six within a individual asci: the fewer the spores in an ascus, the larger they are. Because of their relatively large spore size, Tuber spp. with ellipsoid spores separate readily from the other fungi with similarly ornamented spores. Globose-spored species of Tuber may key out with Elaphomyces spp. which, however, are usually gray-brown, olive-brown, or red-brown in contrast with the pale brown to dark brown Tuber spores. Spores of Paradoxa monospora resemble those of the longest-spored Tuber spp., but Paradoxa spores are much broader than those of any Tuber species.

View photos of Tuber spores

Sporocarp Characters

Shape and Size: Subglobose to irregular and deeply lobed and furrowed, 0.5-12 cm in diameter.
Peridium: White to yellow-brown, red-brown, or black, smooth to scurfy or strongly verrucose, usually with furrows paler than the rest of the peridium where internal veins of tissue emerge. Sometimes with an apical, lateral, or basal cavity.
Gleba: Solid, white to gray in youth but gradually becoming brown to black as spores mature, with meandering white to gray-yellow veins that often emerge throughout the peridium.
Odor: Usually prominent at maturity, often pungent, garlicky, or wine-like.

View photos of Tuber sporocarps

Name Derivation

The ancient Latin word for truffle (Fries, 1823).

Distribution

In forests of ectomycorrhizal hosts throughout the world.
Season: Throughout the year when not limited by dry or cold weather.
Species known from North Temperate Forests: About 60 described and numerous others yet undescribed.

Keys and Descriptions

This large and important genus has never been satisfactorily monographed. Gilkey (1939, 1954) treated what was known at that time of the North American species. European species are variously keyed and described by Malençon (1938), Fischer (1938), Hawker (1954), Lange (1956), Ceruti (1960), and Montecchi and Sarasini (2000). Additional North American species have been described by Colgan and Trappe (1997) and Trappe and Castellano (2001).